The invention concerns a connecting arrangement for joining together at least two components to form a structural assembly, in particular in the region of a wing of an aircraft, wherein at least one component is formed from a fibre composite plastic and at least one further component is formed from a metal, or at least two components are formed from a fibre composite plastic.
Furthermore the invention concerns a method for joining together at least two components, in particular by means of a connecting arrangement, to form a structural assembly, in particular in the region of a wing of an aircraft, wherein at least one component is formed from a fibre composite plastic and at least one further component is formed from a metal, or at least two components are formed from a fibre composite plastic.
In modern aircraft construction alongside the traditional homogeneous aluminium form of construction of the primary structure the hybrid form of construction using metallic materials and fibre composite plastics is being deployed to an increasing extent. The combination of the different materials requires the deployment of a multiplicity of joining techniques and connecting elements. As fibre composite plastics carbon fibre reinforced thermosetting or thermoplastic plastics (CFRPs) are preferably deployed, while metallic components are preferably made from light metal alloys, such as, for example, titanium or aluminium alloys. Furthermore components from stainless steel alloys are also deployed.
From DE 20 2007 019 163 U1 a high-performance press fit securement device for composite material applications is of known art. In the case of this connecting element, i.e., a sleeve rivet, a sleeve with a conical widening in the head region is introduced into a hole passing through the components that are to be joined. The sleeve is then radially expanded by the insertion of the locking ring pin, (the so-called sleeve fastener), in order to achieve a secure press fit within the through hole and a durable connection of the components. By means of the sleeve the risk of a delamination in the hole reveal region of the fibre composite components that are involved is reduced.
Such sleeve rivets required a complex installation process. Lightning strike protection (LSP), which is inevitably required in the case of CFRP components by virtue of their low intrinsic electrical conductivity, in the form of conductive mesh-type surface entities (so-called copper meshes), which at the same time can serve as earth return paths, can only be attached with a reliable level of contact to metallic components with much effort using the sleeve rivets of known art. Moreover the test evidence for a level of electrical contact in accordance with the regulations can only be obtained with difficulty. Furthermore the sleeve rivets generate high procurement and installation costs. In addition with the conventional sleeve rivets aerodynamic requirements can be satisfied only with difficulty, and ensuring the integrity of the sealing of the wing tanks proves to be difficult. In addition the visual impression after painting of wing components punctuated with sleeve rivets is impaired by the sleeve.
In addition from US 2011/0182692 A1 a securing element with a sleeve and a threaded nut, together with a method for their use, are of known art. The sleeve features an essentially hollow cylindrical two-part shank, which can be secured by radial expansion in a through hole of a workpiece by means of a press fit. The shank continues into a cage-type collar, which after the radial expansion of the sleeve sits against a workpiece surface. In the collar the threaded nut is accommodated loosely, for purposes of tolerance compensation, but such that it cannot be lost. A threaded bolt is, for example, screwed into the threaded nut for purposes of attaching a further component.